1. Field of the Invention
The present invention is concerned with an iris retaining device adapted for use by eye surgeons in order to enlarge and maintain the pupillary opening of a size to facilitate surgical procedures such as the implantation of intraocular lenses. More particularly, it is concerned with such an iris retaining device which in preferred forms comprises an elongated, arcuate, flexible body size to fit within the inner defining margin of the iris of a human eye and with specially configured sidewall portions for engaging the inner defining margin of the iris.
2. Description of the Prior Art
Modern day treatment for the condition of cataracts very often involves removal of the crystalline lenses of the patient's eye, followed by implantation of replacement lenses. Such intraocular lenses (IOL's) are commonly implanted within the capsule of the eye, behind the iris.
In surgical procedures, the eye surgeon typically dilates the eye, installs instrumentation to maintain the iris in an expanded position, and makes an incision in the anterior wall of the capsule so as to permit removal of the patient's natural lens. At this point, the IOL is inserted and properly emplaced, followed by necessary final sutures in the cornea.
As can be appreciated, surgery of this type involves working in extraordinarily close quarters with a minimum of clearances. One difficult problem confronted by the surgeon in this context is the presence of the iris positioned anteriorly of the capsule and the tendency of the iris to contract and thus create severe clearance problems. The pupillary opening of the human iris is normally 1-3 millimeters in diameter, but during surgery a larger opening is generally necessary, e.g., 7-9 millimeters. As indicated, the conventional technique is to dilate the eye and employ iris-expanding instrumentation, but this is only partially effective.
In addition to clearance problems, the iris may be readily traumatized during eye surgery, resulting from irrigation solutions used to wash out the cortex of the eye, and instrumentation necessary to retract the iris during surgery. Finally, the iris can also be damaged during implantation of an IOL.